What earthing system do (should!) I have?

[Lobster]

I'm doing some renovating work an old house at the mo, and have turned my attention to the electrics... Today I've been endeavouring to check the various earth cables and bonding arrangements. I've found two old green

6mm(?) earth lead which emerge from the plaster adjacent to the (ancient) fusebox and connect to a terminal block, from which I'd expect to find at least one wire heading for the fusebox, and another heading for the house earth, whatever that is. But as far as I can see(*), nothing; so presumably there's no earthing in the house at all. All I can find is a small, uninsulated, twisted wire dangling down from the terminal block, with an eye in one end, which once upon a time will have been connected somewhere I suppose.

This lot clearly needs some work to sort out; but I am confused about what earthing provision there _should_ be. I've read the FAQ again, but am not clear how I find out what sort of earthing system I have, or should have. Is it up to the electric co to provide one, ie can I whinge at them? Or do I need to fit an earthing rod? If so, where do you put them - this is a solid floor house, and the front (which is where the meters are) is directly on to the pavement.

Thanks for any pointers.

David

*It's incredibly difficult to see anything; some k*****ad has installed the gas meter directly in front of the electric meter and board (presumably too close for regs); and then somebody else, equally cerebrally-challenged, has built a large fitted cupboard enclosing the whole lot, in the corner of the room. Best I can do is point my digital camera round the back of the gas meter and then examine the pictures!

[Christian McArdle]

If you would...

Christian.

[Martin Angove]

In case that was too obscure, what Christian is saying is that it would help us enormously if you could take a few shots of the installation (an overview and one or two closeups perhaps), stick them up on a website somewhere and then post the link in this thread.

As you say, sounds like you have an interesting situation and need to get sorted.

Hwyl!

M.

[Owain]

"Lobster" wrote | ... I've found two old green 6mm(?) earth lead which emerge from the | plaster adjacent to the (ancient) fusebox and connect to a terminal | block,

Those might disappear off to water and gas pipes somewhere.

| from which I'd expect to find at least one wire heading for | the fusebox, and another heading for the house earth, whatever that | is. But as far as I can see(*), nothing; so presumably there's no | earthing in the house at all. All I can find is a small, uninsulated, | twisted wire dangling down from the terminal block, with an eye | in one end, which once upon a time will have been connected somewhere | I suppose.

to the fusebox, especially if it is (or an even older one was) metalclad.

It is also possible that there's an earth (ie bonding) from a socket in the kitchen to the cold water main, and that, brought back through the circuit protective conductor to the fusebox, was considered sufficient to earth the whole installation.

Owain

[Lobster]

Yup, I realised! OK, after a protracted session of Noddy does HTML, please have a look at

where I've done my best. Any advice appreciated (and I don't mean 'rip it out and start again'; I think that goes without saying! It's the earthing question I'm most concerned about.)

Thanks a lot David

[BigWallop]

WOW WEEEEEE !!!!!! Rip it out and start again mate!!! If you have an electrical fire at the consumer unit (God Forbid), or a lightning strike to the power supply outside, you won't know anything about it. It would be over for you by the time you got out your seat.

You now need at least a 10mm sq' Green / Yellow sleeved conductor from the consumer side of both the water and gas supplies, and that means even over the short distances you have between the gas and electrical service in the cupboard. These two leads can be connected to a separate block beside the consumer unit and then one other lead directly from the block to your consumer unit earthing bar.

You'll also need a sixteen millimetre (16mm) sq' Green / Yellow from the earthing bar of the consumer unit to the main supply cable of the electrical service headend, which is under the black main fuse block, and properly clamped to the outer braiding of the supply cable.

For one thing, the electrical supply should be at a minimum of 500mm spacing away from any gas supply equipment, and vice versa of course. Next, the gas and electrical supplies should be fully accessible in case of emergency.

The last thing to have been installed inside that cupboard was the gas meter, and it sure weren't fitted by a CORGI engineer. The soldering gives that show away, unless that is, the engineer was going in blind like you had to with the camera.

By the look of it you'll have to, and I mean have to, move either the gas meter or the electrics to one side of the cupboard, and leave the other service supply at the other side. This looks to be the only way you're going to get the 500mm spacing between them in the area you've got to work in.

Rip it out and start again mate. For your own safety.

[Lobster]

Yeah, cool isn't it! Have no fear, 'rip out' is definitely the plan...!

This bit was really the reason for my post, cos I'm not clear about the main 'supply' earth. The other issues I'm Ok with. So I take it that it's possible to confirm that mine is definitely a TN-S system (he says, having just looked at the FAQ again!)? If I scrape away the black crap which seems to cover the electrical service headend, I should find braid there, then? (As you'll appreciate, this is well-nigh impossible to get at to even check, right now).

Yes, fortunately the cupboard is L-shaped (goes round the corner to the right), so it will be quite easy to get the gas meter moved round there.

Thanks for the reply David

[Lobster]

Indeed; one such lead is in fact attached to CW piping below the kitchen sink (which is close to the water main, located at the opposite end of the house) but I haven't confirmed continuity to one of those near the fusebox yet.

Yes that does fit the evidence! If so, I suppose the place is marginally less of a death trap than I thought, but either way, it will be sorted.

Thanks David

[BigWallop]

The service mains cable you have, by what is showing in the pictures, is an older wire armoured type, so it will have a braiding around it. Wither it is properly earth bonded further down the line is another matter, but best to bond it anyway to make sure. Both water and gas services need to be bonded on the consumer side of the installation. This means on the parts of the pipework that go into the house and not on the parts that comes from the outside of the building.

Good luck with it.

[Owain]

"Lobster" wrote | Yup, I realised! OK, after a protracted session of Noddy does | HTML,

will produce an HTML gallery of thumbnails with links to your original images. For linux, try mkgallery

| please have a look at

| where I've done my best. Any advice appreciated (and I don't | mean 'rip it out and start again'; I think that goes without | saying! It's the earthing question I'm most concerned about.)

I'd worry more about the gas than the electrics. I've seen better soldering by blind heroin addicts.

Owain

[N. Thornton]

or they might be disconnected, who knows. Have seen that one before.

You say the house has been rewired recently, but to be honest thats hard to believe from the pics of the fusebox. Partial rewiring might have been done, but the idea that someone managed to gain enough access to that old fusebox is stretching it. And again, if they didnt replace an old and inaccessible 4-way wire fuse only box, or even upgrade it to mcbs, youve got to wonder what they were thinking.

Does the bathroom have equipotential bonding? Is there an electric shower? Electric cooker? Is there an earth wire running down the side of the house exterior?

Clearly youve got to start again, at least in the CU area, but before doing that youve got to get access. I dont know whats going on with the cupboard but you'll have to make at the minimum another access door so you can actually get to things, both to do the work, and for future householder access.

If I knew who'd done the gas job I'd be calling them back to refit it sensibly at no further cost. On second thoughts..... maybe not!

If it were mine I might start by checking resistance from house wiring earth to real earth, as it would at least give a very quick idea of how unsatisfactory things are. If R is high you would have a high risk install there. If R is nice and low that would at least be reassuring on that fairly major point.

I also would check and test all existing circuits, with a setup like that I wouldnt want to make assumptions.

NT

[Dave Plowman (News)]

I'm confused. ;-) If you're not sure about the armoured cable, shouldn't you use an earth spike? Or shouldn't you anyway?

[Dave Plowman (News)]

Not too neat, is it?. But could still be perfectly safe.

[Lobster]

And you know what? According to NPower, the whole setup *is* perfectly safe....

I phone a corgi this morning, to come and shift the gas meter. Corgi: "Sorry, no can do; everything upstream of and including the meter is Transco's responsibility"

I get a nasty feeling coming on.

I phone Transco.

Transco drone "No, we don't do that, it's the responsibility of your gas supplier"

The nasty feeling is definitely materialising...

I phone NPower and explain all the details of my extremely dangerous installation which needs sorting out pronto. NPower drone: "OK I'll pass on your details to the appropriate dept; they will send you out a questionnaire; when you return that they'll send you a quote..." "Whoa! And how long is it likely to take until I get this sorted out" Drone: "Usually 6-8 weeks" "But I'm phoning to get this work done purely because it's a safety issue; it needs doing now, not in two months!" Drone: "Errrrrr just a minute..." Shortly afterwards I am duly passed up the chain of command a bit. Senior Drone: "Could you please explain the problem again?" I do so, in all its gory detail. Senior Drone: "Well it must be safe and OK because none of our agents have ever reported it as being an issue" "But the meter is practically touching the fuse box - they have to be 0.5m apart doesn't it?" Senior Drone: "Well it must be safe and OK because none of our agents have ever reported it as being an issue"

Oh God...

1....2.....3.....4.....5.....6....

Senior Drone: "However, if you prefer a CORGI-registered engineer could do the work for you, if it only needs moving less than 1 metre..." "But.... but..... but...." Senior Drone: ".... Transco changed the rules about 6 weeks ago" "So how do I convince my local Corgi guy about that?" Senior Drone: "Oh you'll need to phone Transco...".

Unbelievable. What do you do? I feel like sending a photo of the installation to Transco by recorded delivery, holding them liable for the safety of the residents, but providing I can convince my corgi to just go in and do the job, I don't think I can be bothered. :-(

David

[Lobster]

You may be right - I can't remember (or find!) what I said about rewiring, but it certainly wouldn't have been that recent; I just meant that it was more recent than the fusebox suggests. I would certainly guess that the gas meter was added later though.

I certainly have lots of checking to do; I agree.

What do you define as 'real earth' - are you refering to the incoming cable sheath? Or an earth rod somewhere (which would be difficult as there's no 'soft' ground anywhere nearby.

Thanks David

[Lobster]

Thanks. Do you do this using the same sort of earth clamp as you'd use for bonding to a water pipe, or is there something different? (I can't find mention of any other sort).

David

[Kalico]

If nothing else, console yourself that you have given some of us here a hell of a laugh.

"Better soldering by blind heroin addicts", indeed.

Jeez, I thought I had problems and now at least I know it is not just me that hates calling these companies.

Good luck with it all.

Rob

Replace 'spam' with 'org' to reply

[BigWallop]

A standard earth strap is ideal Dave, nothing fancy needed mate.

[BigWallop]

LOL !!!

Now I'm wondering where Owain saw a blind heroin addict soldering a gas meter? And doing a better job than the one that done Lobsters meter? :-)) LOL !!!

[Richard Porter]

It used to be common practice to bond the house earth to the rising water main. However with water companies increasingly using plastic piping this is no longer reliable. It's now necessary to bond the house's water system to an independent earth.